Project Summary/ Abstract Growing evidence supports the need to both recognize smokers with substance use disorder (SUD) as a key disparity group in evaluating tobacco-related use and disease, and identify strategies to address this disparity. Smoking frequently co-occurs with other illicit drug and alcohol use and synergistically worsens health. Many who recover from SUD as they age remain dependent on tobacco and are at higher risk for cancer and other smoking-related complications, and mortality (smokers with SUD have mortality rates 4 times higher than non- smokers with SUD). Despite greater nicotine dependence and more difficulty quitting among smokers with SUD, smokers with SUD often report a strong desire to quit, and tobacco dependence treatment (TDT) is effective in this population. Moreover, smoking cessation has repeatedly been shown to improve SUD treatment outcomes, countering the common dismissal of nicotine dependence as a lower priority in SUD treatment. However, rates of TDT in this population remain low. Recently, many states have expanded Medicaid coverage of TDT, but it is unclear whether this has increased use of treatment services in this vulnerable group. Tobacco tax and other tobacco control policies have also successfully reduced smoking rates generally, but effectiveness for smokers with SUD is unknown. We propose to assess the impact of expanded TDT coverage and tobacco excise taxes on use of TDT services, smoking intensity and quit rates for smokers with SUD using the 2004-16 Medicaid Analytic Extract (MAX) claims data from all 50 states, and the 2004-2018 National Survey of Drug Use and Health (NSDUH), merged to datasets of state Medicaid benefits and state-, city-, and county-level tobacco policies. Taking advantage of variation within and between states over time, we apply rigorous methods (difference-in- difference analyses and individual fixed-effects models) to assess causal effects of tobacco cessation policies. In Aim 1, we test the effect of Medicaid TDT coverage on initiation and maintenance of TDT and on quitting smoking among Medicaid beneficiaries with SUD. In Aim 2, we test the effect of increasing cigarette excise taxes on the intensity of smoking and smoking cessation in a broader national sample of individuals with SUD. In Aim 3, we assess the combined effects of TDT and tax policies on tobacco use among Medicaid beneficiaries with SUD. We hypothesize that insurance coverage of TDT incentivizes TDT treatment-seeking, that rising taxes create strong incentives to quit, and that both policies together will amplify quitting rates. We have worked closely with stakeholders to propose analyses that inform decision-makers in complex real-world policy environments with hard-to-reach populations, and we incorporate a dissemination plan that lays the groundwork for actionable policy changes by targeting state tobacco control managers, state SUD services agencies, SUD treatment providers reluctant to incorporate TDT, and integrated behavioral health providers.